For the cleric who runs Iran, there’s no such thing as a pleasant surprise, especially on election day. Ayatullah Ali Khamenei was not pleased when a librarian named Mohammed Khatami was swept into the President’s office in 1997, leading a wave of reformists who challenged the status quo in which Khamenei, as the unelected Supreme Leader of the Revolution, was most heavily invested. In every election cycle since, the self-appointed portion of Iran’s government has done all it can to winnow the choices placed before Iranian voters. On Tuesday, that system tightened the screen once more, disqualifying the only two prominent candidates who dared to differ with the Supreme Leader. When Iranians go to the polls on June 14 to choose a successor to Mahmoud Ahmadinejad, the ballot will run from Khamenei’s former policy director to the man who married his daughter.

“We see in retrospect, the system was absolutely terrified at the possibility of a Gorbachev phenomenon,” says Ray Takeyh, who follows Iran at the Council on Foreign Affairs in Washington. He refers to Mikhail Gorbachev, who engineered the demise of the Soviet empire that its politburo selected him to protect. “Because of Khatami. They don’t want a repeat of that performance.”

Consider the two most prominent candidates barred by the unelected Guardian Council, “the last two guys who weren’t going to completely tow the line,” says Takeyh. Akbar Hashemi Rafsanjani, 78, has served twice as Iran’s President already, in 1989 and 1993. He was an architect of the Islamic revolution that brought Grand Ayatullah Ruhollah Khomeini to power 34 years ago. At one point, when Khomeini thought he was about to be killed, he wrote a will ordering payment of his debts — Rafsanjani was owed the most.

Khamenei owes him a good deal more. After Khomeini’s 1989 death, the assembly of clerics charged with naming a successor was deadlocked until Rafsanjani announced he’d heard Khomeini say Khamenei would be good in the job. But not even that bit of history was enough to undo Rafsanjani’s association with the reform movement that later rose in reaction to the harshness of the mullah’s rule. “It’s a little bit like Kramer vs. Kramer now in the Iranian regime,” says Meir Javedanfar, an Iranian-born analyst in Tel Aviv. “The regime is turning against itself.”

Less surprising was the disqualification of Esfandiar Rahim Mashaei, the man Ahmadinejad named as his Vice President until Khamenei ordered him out of the job in 2009. Mashaei was dubbed part of a “deviant current” after suggesting that perhaps clerics are not necessary to mediate between ordinary people and God. He’s also spoken encouragingly of Iranian nationalism, a potent residual force in a nation that predates the arrival of Islam by more than a millennium. “And everybody knows the Leader can’t stand him,” says Takeyh.

His association with Ahmadinejad underscores the perils of elections. Loathed by the West for denying the Holocaust, Ahmadinejad looked like the savior of the Iranian establishment when he burst onto the national stage in the 2005 presidential election. In Iran’s elitist politics, his populist appeal was real and profound and Khamenei embraced him “almost as the son he never had,” says Javedanfar. The Leader mobilized the establishment to assure the young ideologue was re-elected in 2009, allowing the appearance of vote fraud so massive, it brought hundreds of thousands of Iranians into the streets and left scores dead. But in the second term, Ahmadinejad challenged Khamenei’s authority repeatedly — and more directly than Khatami ever dared. The mild-mannered reformist was so averse to confrontation that in the moment of one election showdown he was admitted to the hospital, complaining of back spasms.

“They’re trying to do the election this time completely different from 2009,” says Takeyh. Security has been stepped up, and the Internet slowed down. “What they want to do is get through this electoral cycle with maximum degree of public apathy.” The field of candidates should help there. The Leader’s reported favorite is Saeed Jalili, who before heading the negotiating team on Iran’s nuclear program ran Khamenei’s office. Also approved to run was former Foreign Minister Ali Akbar Velayati, Tehran Mayor Mohammad-Bagher Ghalibaf, former nuclear negotiator Hassan Rowhani, and former parliament speaker and Khamenei son-in-law Gholam Ali Haddad-Adel.

It is a not a diverse field. As the screening of candidates has grown more exacting, the base of Iranian politics has narrowed to a thinness that analysts describe as perilous. The press, which a decade ago was still lively, now reflects a political spectrum running from A to B: “Principlists” square off against “traditional conservatives.” Everyone else is on the outside peering in. “The smaller the circle becomes, the worse the legitimacy,” says Javedanfar, who lectures on Iran at the Interdisciplinary Center north of Tel Aviv. “There’s also the fact that those who are in are not the sharpest tools in the box.”

On the other hand, it may not be a great time for the mullahs to court unnecessary risks. Iran’s economy is crippled by international sanctions aimed at diminishing its nuclear program, and Tehran’s only military ally — Syrian strongman Bashar Assad — is fighting for his life, along with that of the Hizballah militia that Iran sponsors in adjacent Lebanon.

“They may actually succeed in stage-managing this thing. They threw out the two candidates who potentially could have caused trouble,” says Takeyh. “But you never know. Who’d have predicted in 2009 that a has-been like Mir-Hossein Mousavi would have inspired massive street protests? In 2009 they invited 400 foreign journalists into the country to watch. Did they expect things to go wrong?”

Karl Vick has been TIME's Jerusalem bureau chief since 2010, covering Israel,the Palestine territories and nearby sovereignties. He worked 16 years at the Washington Post in Nairobi, Istanbul, Baghdad, Los Angeles and Rockville, MD.